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Re: dW turns into dQ



Bob wrote:


This might be compared to asking, in F=mA, "if F includes the sum of
electrical, gravitational, etc forces and only their (vector)
sum matters
for calculating A, why the partitioning?" Of course it is
because this
partitioning is our way of enabling the calculation of that
sum, but the
resulting A wouldn't care if you used a different
partitioning (taxonomy
of F) so long as you applied the same vector sum.

Bob

I wonder???? I realize that in your above analogy, it is only an analogy;
but I have a gut feeling that it is different. The partitioning in the NII
example above, is in essence a coordinate system choice. And the physics
doesn't care what coordinates you choose to describe the process with.

In thermodynamics . . . my gut tells me the physics probably does care
whether something is dQ or dW (of course that gut feeling may simply be the
brownie I just ate). . . Namely we also have the 2nd law (of thermodynamics)
to worry about . . . but to what degree?

I don't think such a big deal would be made out the distinction if something
so analgous were the case. (and hence such a long phys-L discussion)

Joel



Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor



. . .
If the partitioning is totally arbitrary once a specific process and
time-scale is determined, why bother partitioning at all?
. . .
Joel